A blockchain- and IoT-based smart product-service system for the sustainability of prefabricated housing construction Clyde Zhengdao Li, Zhe Chen, Fan Xue, Xiang T.R. Kong, Bing Xiao, Xulu, Lai, and Yiyu Zhao This is the peer-reviewed post-print version of the paper: Li, C. Z., Chen, Z., Xue, F., Kong, X.T.R., Xiao, B., Lai, X. & Zhao, Y. (2021). A blockchain- and IoT-based smart product-service system for the sustainability of prefabricated housing construction. Journal of Cleaner Production, Article ID 125391, In press. Doi: 10.1016/j.jclepro.2020.125391 The final version of this paper is available at: https://doi.org/10.1016/j.jclepro.2020.125391. The use of this file must follow the Creative Commons Attribution Non-Commercial No Derivatives License, as required by Elsevier’s policy. Abstract: Prefabricated housing construction (PHC) will be widely recognized as a contributor to consumption reduction and sustainability enhancement if inherent drawbacks (e.g., fragmented management, poor connectivity) can be addressed efficiently. The promotion of advanced information and communication technologies (ICT) has triggered the evolvement of smart product-service systems (SPSS), where a smart connected product (SCP) acts as a critical role in the interconnection of physical components and specialized services for value co-creation. Hence, it is promising to realize the positive improvement of PHC based on an SPSS approach, especially during the challenging post-COVID-19 pandemic era. We developed an intelligent platform based on service-oriented manners with practical case demonstration for interactive innovation of PHC shareholders, among which prefabricated components (PC) have been defined as the SCP in PHC, and a platform-enabled approach has also been adopted in the way of SPSS. Furthermore, distributed security technology viz. blockchain along with inclusive ICT (e.g., Internet-of-Things (IoT), Cyber- Physical System (CPS), and Building Information Modeling (BIM)) are employed jointly to spark new modes of smart construction. Meanwhile, valuable exploration and open research directions are expected to facilitate the PHC supply chain to become more resilient in sustainability. 1 Keywords: Prefabricated Housing Construction; Smart Product-Service Systems; Blockchain; Internet of Things; Sustainability Nomenclature BIM Building Information Modeling BT Blockchain Technology CPS Cyber-Physical System DLT Distributed Ledger Technology ICT Information and Communication Technologies IoT Internet of Things PC Prefabricated Components P2P Peer-to-Peer PHC Prefabricated Housing Construction PSS Product-Service Systems RFID Radio Frequency IDentification SCM Supply Chain Management SCP Smart Connected Product SCR Supply Chain Resilience SPSS Smart Product-Service Systems 2 1 1. Introduction 2 Sustainability, as one of the core issues drawing global attention, has played a crucial role in 3 the construction industry through the ages (Du et al., 2019). Previous research indicated that 4 the construction industry’s carbon emissions and worldwide energy usage have incrementally 5 increased, accounting for 30% (Pan and Garmston, 2012) and 40% (John et al., 2016), 6 respectively. Meanwhile, without effective strategies, the volume of its consumption will 7 keep rising by approximately 50% by 2050 (IEA, 2013). In this perspective, the 8 transformation of the construction industry is particularly critical for environmental 9 conservation and sustainable development. Prefabricated housing construction (PHC), with 10 its widely recognized contributions, such as decrease of schedule delay (Gao and Tian, 2020), 11 saving of labor usage (Li et al., 2018), reduction of construction waste and carbon emission 12 (Zhou et al., 2019b), has become a trend in lean construction. However, if PHC cannot 13 overcome its intrinsic drawbacks (e.g., low productivity, poor interoperability, inefficient 14 management, etc.), it can hardly become an eligible contributor to sustainability (Du et al., 15 2019). 16 PHC relies on the stable operations of supply chains (Teng and Pan, 2019), which 17 mainly includes building design, prefabricated components (PC) production, logistics, and 18 prefabrication assembly. Moreover, sustainable supply chains are committed to providing 19 shareholders with satisfactory products as well as valuable services in an economized and 20 environmental-friendly manner to meet particular needs (Li et al., 2018). Goedkoop (1999) 21 firstly defined such a proposition as product-service systems (PSS); thereafter, PSS has been 22 extensively regarded as an economic and energy-saving method to realize sustainability (Liu 23 et al., 2018). Recently, emerging information and communication technologies (ICT), for 24 instance, Cyber-Physical Systems (CPS), Building Information Modeling (BIM), Internet-of- 25 Things (IoT), and blockchain, have triggered a promising evolution of PSS, which is known 26 as smart PSS (SPSS) (Valencia et al., 2015). Moreover, the smart connected products (SCP) 27 and its delivered e-services served as the essential constitution of SPSS (Zheng et al., 2018). 28 By transforming from product-centered to service-centered, SPSS will give rise to the next 1 29 generation of ICT-driven productivity growth (Porter et al., 2014). Besides, once products 30 and services are recognized as a bundle, digital services are more capable of satisfying the 31 requirements of shareholders compared to exclusively employing physical products (Zheng et 32 al., 2019a). 33 Specifically, as for PHC, it has several construction sites, long construction cycles, large 34 industrial chains, and various uncertain situations (Araújo et al., 2020), inevitably generating 35 mass data which can be categorized into two types: shareholder-generated and product- 36 generated (Zheng et al., 2018). Shareholder-generated data are mainly stemmed from mutual 37 communication among designers, producers, transporters, and assemblers, while product- 38 generated data can be regarded as its status information captured by machines from particular 39 stages. However, owing to the lack of practical approach to fully utilize plentiful data, even 40 worse, fragmentation of information frequently can hinder collaboration in the supply chain. 41 As a result, the conventional PHC faces several challenges in weak interaction and smart 42 decision-making (Tao et al., 2019). Besides, the PHC supply chain is a network of cross- 43 echelon organizations that are connected by information, material, services, product flows, 44 and capital flows among stakeholders (Gao and Tian, 2020); thus, making reliable products 45 and value-added digital services as a bundle is paramount (Zheng et al., 2019b). 46 As a result, it is feasible to realize the promotion of PHC based on SPSS. PCs can be 47 regarded as SCP. Integrated ICT enables various shareholders to acquire SCP status data on a 48 real-time basis while connecting diverse stages, responding promptly to disturbing incidents, 49 and realizing the reduction of energy consumption. Nevertheless, the application of SPSS has 50 been embraced in manufacturing industries (e.g., smart devices, machine tools, etc.). Scarcely 51 related works demonstrate the connection between SPSS and the construction industry (PHC 52 particularly), and very few works of literature concentrate on how services and products can 53 be integrated as a bundle to fulfill users’ specialized needs. Furthermore, the platform-based 54 approach was considered as a fundamental method to leverage the value of SPSS (Thomas et 55 al., 2014), and diverse PHC stages should be centralized to make the supply chain more 56 resilient, which also shows inadequate support in the literature. 57 To address the given limitations, this article develops an intelligent platform based on 2 58 inclusive technologies, incorporating CPS, IoT, BIM, and blockchain for SPSS innovation in 59 PHC. The research objectives are: (1) to develop a smart platform to gather, process, 60 communicate, and leverage information through the lifecycle of PHC; (2) to employ 61 blockchain- and IoT-based, BIM- and CPS-enabled platform to facilitate the real-time 62 management of PHC supply chain; (3) to demonstrate the effectiveness and performance of 63 the proposed platform based on SPSS approach with the practical application. 64 The remainder of the paper is organized as follows: Section 2 presents a holistic review 65 of related works. In Section 3, we illustrate the architecture of the platform. Then, we 66 introduce the function development of the platform in Section 4, followed by a real-life case 67 study that employs the proposed platform based on SPSS in Sections 5. The conclusions and 68 directions for future research are summarized in Sections 6. 69 2. Related works 70 2.1 Prefabricated housing construction 71 PHC, with its generally recognized benefits of standardized production, associated services, 72 and energy-saving construction, has been regarded as an eligible contributor to handling 73 various building challenges (Teng et al., 2018). Compared to cast-in-situ techniques 74 characterized by dense scaffolds, dusty installation, wet working, formwork systems, and 75 massive demolition waste, PHC aims to transfer as many on-site construction components as 76 possible to manufacturing factories under standard regulations and controllable production 77 patterns (Li et al., 2020). As a result, the advantages include, but are not limited to, 78 construction cost and time savings, enhanced